1. Field of the Invention
This invention relates to organic compositions stabilized against degradation upon exposure to light. More particularly, the present invention relates to the discovery of new UV absorbers for organic compositions. More specifically, certain copper chelates of 2-hydroxybenzophenones have been discovered to be useful UV light absorbers for organic compositions such as polymer compositions. More specifically, certain polymer compositions such as polyparabanic acids, poly(iminoimidazolidinediones), polyurethanes, polyureas, polyesters, polyamides, polyimides, polycarbonates, polyhydantoins and polymers containing one or more moieties characteristic of these polymers can be stabilized against degradation upon exposure to light by adding to the polymers copper chelates of 2-hydroxybenzophenones. The invention further relates to the method of preparing organic compositions which are stabilized against degradation upon exposure to light.
2. Description of the Prior Art
In U.S. Pat. No. 4,022,751 entitled STABILIZATION OF HIGH TEMPERATURE PLASTICS CONTAINING ARYLMETHYLENE ARYLENE GROUPS AGAINST THERMAL OXIDATIVE DEGRADATION, of Burnett H. Johnson, issued May 10, 1977 there is disclosed that chelates of copper, nickel and cobalt can be usefully employed for the stabilization of high temperature plastics such as polyparabanic acids against thermal oxidative degradation. Examples of compounds which can form chelates with copper are dicarboxylic acids, e.g., malonic acid; diamines, e.g., ethylenediamine and o-phenanthroline; amino acids, e.g., ethylenediamine tetra acetic acid; hydroxy acids, e.g., citric acid; phosphates, e.g., pyrophosphoric acid; nitro acids, e.g., nitroacetic acid; hydroxy aldehydes, e.g., salicylaldehyde; .beta.-diketones, e.g., acetylacetonates; phenols, e.g., 3-hydroxyquinoline and keto esters, e.g., ethylacetoacetate. The patent neither discloses that the copper chelate compounds disclosed therein are useful as UV light absorbers nor discloses copper chelates of 2-hydroxybenzophenones.
It is also well known that certain 2-hydroxybenzophenones are useful as light absorbers. For example, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone and trihydrate of 2-hydroxy-4-methoxybenzophenone have been commercially sold for use as UV light absorbers to be employed with organic compositions which can degradate upon exposure to light.
Polyparabanic acid compositions and their properties are disclosed in U.S. Pat. Nos. 3,661,859; 3,635,905; 3,547,897 and 3,591,567 which are hereby incorporated by reference in their entirety.